六年级上册第四单元确定起跑线市名师优质课比赛一等奖市公开课获奖课件.pptx

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,确定起跑线,第1页,1,3,2,终点线,第2页,第3页,第4页,85.96m,72.6m,1.25m,1.25m,1.25m,第5页,第6页,85.96m,72.6m,1.25m,1.25m,1.25m,第7页,第8页,1,2,3,4,5,6,7,8,直径(m),周长(m),全长(m),注：取,3.14159,第9页,85.96m,72.6m,第一道,直径：,周长：,全长：,72.6m,72.63.14159228.08（m）,85.962228.08=400（m）,第10页,1,2,3,4,5,6,7,8,直径(m),周长(m),全长(m),72.6,228.08,400,注：取,3.14159,第11页,85.96m,72.6m,第一道,直径：,周长：,全长：,72.6m,228.08m,400m,第二道,直径：,周长：,全长：,72.6,1.251.25=75.1（m）,75.1,3.14159235.93（m）,85.962,235.93,=407.85（m）,1.25m,1.25m,第12页,1,2,3,4,5,6,7,8,直径(m),周长(m),全长(m),72.6,228.08,400,75.1,235.93,407.85,注：取,3.14159,第13页,85.96m,72.6m,第二道,直径：,周长：,全长：,75.1m,235.93m,407.85m,第三道,直径：,周长：,全长：,75.1,1.251.25=77.6（m）,77.6,3.14159243.79（m）,85.962,243.79,=415.71（m）,1.25m,1.25m,75.1m,第14页,1,2,3,4,5,6,7,8,直径(m),周长(m),全长(m),72.6,228.08,400,75.1,235.93,407.85,77.6,243.79,415.71,注：取,3.14159,第15页,85.96m,72.6m,第三道,直径：,周长：,全长：,77.6m,243.79m,415.71m,第四道,直径：,周长：,全长：,77.6,1.251.25=80.1（m）,80.1,3.14159251.64（m）,85.962,251.64,=423.56（m）,1.25m,1.25m,77.6m,第16页,1,2,3,4,5,6,7,8,直径(m),周长(m),全长(m),72.6,228.08,400,75.1,235.93,407.85,77.6,243.79,415.71,80.1,251.64,423.56,注：取,3.14159,第17页,85.96m,72.6m,第四道,直径：,周长：,全长：,80.1m,251.64m,423.56m,第五道,直径：,周长：,全长：,80.1,1.251.25=82.6（m）,82.6,3.14159259.50（m）,85.962,259.5,=431.42（m）,第18页,1,2,3,4,5,6,7,8,直径(m),周长(m),全长(m),72.6,228.08,400,75.1,235.93,407.85,77.6,243.79,415.71,80.1,251.64,423.56,82.6,259.5,431.42,注：取,3.14159,第19页,85.96m,72.6m,第五道,直径：,周长：,全长：,82.6m,259.5m,431.42m,第六道,直径：,周长：,全长：,82.6,1.251.25=85.1（m）,85.1,3.14159267.35（m）,85.962,267.35,=439.27（m）,第20页,1,2,3,4,5,6,7,8,直径(m),周长(m),全长(m),72.6,228.08,400,75.1,235.93,407.85,77.6,243.79,415.71,80.1,251.64,423.56,82.6,259.5,431.42,85.1,267.35,439.27,注：取,3.14159,第21页,85.96m,72.6m,第六道,直径：,周长：,全长：,85.1m,267.35m,439.27m,第七道,直径：,周长：,全长：,85.1,1.251.25=87.6（m）,87.6,3.14159275.20（m）,85.962,275.2,=447.12（m）,第22页,1,2,3,4,5,6,7,8,直径(m),周长(m),全长(m),72.6,228.08,400,75.1,235.93,407.85,77.6,243.79,415.71,80.1,251.64,423.56,82.6,259.5,431.42,85.1,267.35,439.27,87.6,275.2,447.12,注：取,3.14159,第23页,85.96m,72.6m,第七道,直径：,周长：,全长：,87.6m,275.2m,447.12m,第八道,直径：,周长：,全长：,87.6,1.251.25=90.1（m）,90.1,3.14159283.06（m）,85.962,283.06,=454.98（m）,第24页,1,2,3,4,5,6,7,8,直径(m),周长(m),全长(m),72.6,228.08,400,75.1,235.93,407.85,77.6,243.79,415.71,80.1,251.64,423.56,82.6,259.5,431.42,85.1,267.35,439.27,87.6,275.2,447.12,90.1,283.06,454.98,注：取,3.14159,各跑道起跑线应该相差多少米？,7.85m,/7.86m,7.85,7.86,7.85,7.86,7.85,7.85,7.86,第25页,1,2,3,4,5,6,7,8,直径(m),周长(m),全长(m),72.6,228.08,400,75.1,235.93,407.85,77.6,243.79,415.71,80.1,251.64,423.56,82.6,259.5,431.42,85.1,267.35,439.27,87.6,275.2,447.12,90.1,283.06,454.98,注：取,3.14159,第26页,我不用算出每条跑道长度，也知道它们相差多少米?,两条直道是一样，所以只需要看圆周长。圆周长是这么算：,第一道：72.6,第二道：(72.62.5)=,72.6,2.5,第三道：(75.12.5),=75.1,2.5,第四道：(77.62.5),=77.6,2.5,第五道：(80.12.5),=80.1,2.5,第六道：(82.62.5),=82.6,2.5,第七道：(85.12.5),=85.1,2.5,第八道：(87.62.5),=87.6,2.5,每一条跑道都在上一条跑道基础上增加2.5长度。你能算出2.5是多少米吗？,第27页,终点,起点,200米跑道，每条道长度都是它们全长二分之一。,第一条：4002=200（m）,第二条：407.852=203.925（m）,第三条：415.712=207.855（m）,第四条：423.562=211.78（m）,第五条：431.422=215.71（m）,每条道相差3.925m或3,39m。所以起跑线应依次提前约3.925m。,思索：200米跑步比赛，跑道宽为1.25米，起跑线应依次提前多少米？,第28页,谢谢同学们,坚持！,第29页,